Camping Griswalds,
This attraction is unbelievable. There is nothing like it anywhere. The launch into space is a prolonged G-force that drains the blood from your face! And the launch is followed by a near weightlessness feeling. Astronauts have confirmed that the launch experience is realistic. The ride is now open intermittently. Ask any cast member (especially the one in front of the digital Tip Board just past Spaceship Earth) if the attraction is open. I recommend FASTPASS during early entry or anytime it's available, or using the Singles Line (if the wait isn't too long and your family is willing to split up).
Steven Barrett, author of the "Hassle-Free Walt Disney World Vacation" and the "Hidden Mickeys of Walt Disney World" book, both books published by The Intrepid Traveler Publishers